Project Summary

Tick-borne diseases (TBDs) represent a major public health threat in North America, particularly for military personnel training on Department of Defense (DoD) installations. We received funding from the Strategic Environmental Research and Development Programto explore several of the predicted consequences of climate change on fire regimes and plant communities, and their interactions with wildlife, for human risk of exposure to TBDs in the southeastern U.S.

Our specific objectives are to:

  1. Evaluate the interactions between fire and plant invasions spanning a gradient in fire management, invasive plant distribution and abundance, and climatic conditions across the southeastern U.S.

  2. Quantify the effects of fire and plant invasions and their interactions on wildlife abundance, tick abundance, tick infection rates, and TBD risk to humans.

  3. Calibrate a spatially explicit model of TBD risk in response to fire-invasion interactions and examine the responses of fire, plant invasions, wildlife, TBD risk, using simulations of climate change scenarios.

Number of plots sampled

There were 13 plots established and sampled at Fort Jackson.

Range of fire history sampled at Fort Jackson

We established plots in areas at Fort Jackson ranging in time since last fire from 0 to 11 years.

Tick Overview - Species

Lone star ticks, Amblyomma americanum

abbreviation: Am. am.

Gulf coast ticks, Amblyomma maculatum

abbreviation: Am. mac.

American dog ticks, Dermecentor variablis

abbreviation: De. var

Brown dog ticks, Rhipicephalus sanguineus

abbreviation: Rh. san

Black-legged or deer ticks, Ixodes scapularis

abbreviation: Ix. sc

Tick abundance

The figure below shows the general relationship between the abundance of adult and nymph life-stage ticks (observations of larvae were counted as “1”) across all the installations. The points contributed by Fort Jackson are highlighted in red. The y-axis (tick abundance) is natural-log transformed, i.e., a value of 2 corresponds to exp(2) = 7.3890561. The total number of ticks collected at Fort Jackson was 0.

Canopy cover

Host and Dung Relationships

Cogongrass

Plant species and herbaceous data

Trees

Supplementary Information - Tick Survival Assay

Supplementary Information - Cogongrass fire temperatures from small scale experiments